Mold Silicone - Hard (40 Shore a) 1 kg

EUR 38,69

Mold Silicone – Hard (40 Shore A) is a liquid silicone commonly used for creating durable and stable casting molds. This is the hardest silicone we offer, making it ideal for producing molds that require dimensional stability and rigidity. The silicone is easy to work with, releases cleanly from the mold, and is non-toxic. It is white in color but can be tinted using our silicone pigments or natural color pigments. PRO pigments are not compatible with silicone.

This product is a tin-cure (condensation) silicone.

Usage:

The silicone must be mixed with the included curing agent. 1 kg of silicone equals approximately 0.8 L.
For smaller batches, an injection syringe can be used for precise hardener measurement, though this can be challenging. For easier mixing we recommend our Heat-Resistant Silicone, which has a 1:1 mixing ratio.
Note: Adding more than 3% curing agent will reduce curing time, wile using less will extend it.

Always wear gloves when working with silicone, as it is sticky and can be difficult to remove from skin.

Storage & Shelf Life:

Shelf life: 12 months
Optimal storage temperature: 5-10°C
Can be stored at higher temperatures, but not above 25°C

Important:

This silicone has no EU food safety certification, but our Heat-Resistant Silicone is FDA approved for food contact.

Learn more about this silicone and its applications below:

Description

Mold Silicone - Hard (40 Shore A) - Technical Data:

Working time: max. 20 min
Curing time: approx. 5 hours
Hardness (shore A): 40
Color: White
Viscosity: approx. 19000 mPa.s
Elasticity: 300%
Tensile strength: 4,0 MPa
Tear strength: 23 kN/m
Shrinkage: <0.2%
Melting point: 160ºC

Note: Data applies at 25°C room temperature.

Effecient Silicone Usage for Mold Production
Plan your silicone requirements accurately to optimize material use and reduce waste:

Choose a mold box with at least 1 cm clearance on all sides of your object.
Calculate the total box volume (Length x Width x Height).
Subtract the object’s volume using water displacement or CAD data
Convert volume to silicone weight: 1 kg silicone ≈ 800 cm³.

Example: A 15 × 9 × 10 cm mold box = 1350 cm³. Object volume = 230 cm³ → net silicone volume = 1120 cm³. Required silicone = 1120 ÷ 800 ≈ 1.4 kg.

Mixing and Working with Silicone

Each container of curing agent is designed for 1 kg of silicone.
Mix only the amount you need for the project.
Maximum working time after mixing: 20 minutes.

Forming and Layering

When creating multi-part molds, apply a thin layer of release agent on the cured silicone to prevent the new layer from bonding.
Same principle applies when casting silicone into a silicone mold: always use release agent to prevent adhesion between layers.

Tips

Use gloves when handling silicone.
Apply thin first layers to capture all details before adding thicker layers (5-10 mm) for mold strength.
Silicone cures at room temperature but can be accelerated with controlled heat.

Video Tutorial

Watch our step-by-step guide for casting silicone, demonstrating proper techniques including layering, release agent application, and mold finishing. Materials used in the tutorial include modeling clay, a cardboard box, petroleum jelly, and elastic bands.

Data Sheet: Mold silicone 30, 40, 50 - click here

Data sheet: Catalyst for Liquid silicone - click here